High performance tachometer with automatic triggering

ABSTRACT

A high performance tachometer with memory device electronically connected to an input signal. A triggering device autometrically indicates the start of a drag racing event and activates the memory device. The memory device records only the racing event.

CROSS REFERENCES RELATED APPLICATIONS

This application is a continuation of U.S. Ser. No. 08/649,018, filedMay 16, 1996, still pending.

BACKGROUND OF THE INVENTION

1. Field of the Art

The present invention relates to tachcmeters, and more particularly, tohigh performance automotive tachometers.

2. Discussion of the Related Art

In the world of high-speed autoracing, extreme demands are placed onboth car and driver. Nowhere is this more true than in the realm ofhigh-speed, short-duration racing, such as drag racing. In these races,drivers command high performance vehicles to accelerate throughone-quarter mile of roadway in approximately seven seconds, reachingspeeds of over 200 miles per hour. Frequently, the drivers and vehiclesare so competitively matched that as little as one thousandth of onesecond can make the difference between winning and losing a race.Accordingly, drivers look for any way to improve their performance andconsistency, even if only by the smallest of margins.

In this regard, drivers train heavily on effective gear shifting. Duringa typical, seven second racing interval, the driver must normally shiftthrough four or five gears. Indeed, in the professional drag racingcircuit driving skill plays a significant role in the outcome of therace. Not only should the driver be able to shift quickly and cleanly,but the driver should also shift at the appropriate engine speeds toextract the maximum power and racing speed from the vehicle. To be sure,the characteristics of any given vehicle (e.g., engine tune,transmission gearing, tires, body aerodynamics, etc.) combine to definea maximum performance curve for each gear of that vehicle. Thisperformance curve, in turn, defines the optinum engine speed for eachgear at which the driver should shift in order to effect maximum speedfrom the vehicle. In addition to rote practice, however, drivers alsolock to instrumentation or other driving aids to help them properly timeand execute these critical shifts at the appropriate points along thepower curves.

Of course, tachometers have long been known to provide a vehicleoperator with an instantaneous display of engine speed. In the area ofhigh performance vehicles, however, tachometers offer special featuresto provide the extra assistance demanded by the drivers. As an example,some tachometers have a multiple range dial display that expands thecritical portion of the dial display. For example, on a circular gaugehaving a display preprinted near the circumference of the dial face,different scale gradients are provided for different engine speedranges. Since the lower engine speeds are of lessor significance to thedriver for shifting purposes, the scale displaying these lower enginespeeds, for example up to 6,000 RPM, is compressed into a small portionof the dial scale display, while the scale displaying higher enginespeeds, from 6,000 RPM to 11,000 RPM for example, is expanded to coverthe remainder of the dial scale display. In this fashion, the driver canmore particularly identify the engine speed in the range surrounding thecritical shift points. This type of tachometer can be referred to as a"double range" tachometer.

One known tachometer in the prior art to offer this double range scaleutilizes a stepper motor to drive the tachometer pointer or deflectionneedle. The particular advantage realized by the use of stepper motorsis that it is technically easier in a digital circuit to control thedeflection needle throughout both the compressed and expanded regions ofthe dial scale display.

A shortcoming in a stepper motor system, however, resides in theinherent characteristics and limitations of the stepper motor. Sincestepper motors are rotated in discrete increments, movement of thetachometer deflection needle is jerky, rather than in smooth, fluidmotion. More significantly, the response time of stepper motors istypically too slow for fast revving engines, such as dragster engines.As a result, the engine speed displayed by the tachometer deflectionneedle lags the actual engine speed. The amount of this "lag" dependsupon the rate that the engine speed is changing. This is particularlyproblematic when the driver targets a specific engine speed at which toshift, since the actual engine speed will be slightly different than thedisplayed speed.

Other double range tachometers may have the deflection needle controlledby D'arsonval meters. Like stepper motors, however, D'arsonval metersare also characterized by a poor response time that is typically tooslow for effective use on dragsters. Furthermore, D'arsonval motorstypically have poor vibration resistance, which makes them ill-suitedfor use on dragsters.

Other engine speed sensing devices are known to provide what can beglobally referred to as "RPM switches." These RPM switches are typicallyindividual, stand-alone units adapted to monitor the engine speed andsignal or otherwise act upon the detection of certain desired enginespeeds. RPM switches are used in a variety of applications such ascontrolling nitrous oxide injectors, limiting the engine RPM,controlling system ignition timing, and operating shift lights, just toname a few. In a particular vehicle, one RPM switch may be dedicated tocontrol a nitrous oxide injector in such a fashion that the nitrousoxide is controllably injected when the vehicle reaches a preprogrammedengine speed. Similarly, a second RPM switch may be dedicated tocontrollably advance and retard the ignition timing depending upon theengine speed. A further RPM switch may be dedicated to control a shiftlight, which illuminates at certain preprogrammed engine speeds toprompt the driver to shift gears. Indeed, shift lights are known to beprovided in connection with a RPM switch imbedded within the tachometer.

However, there are various shortcomings in connection with these priorart systems. One shortcoming is the elevated system cost due to numberof excess components required by the individual RPM switches. A moresignificant shortcoming is the compromise of the overall systemintegrity that results in the various component intolerances,particularly where two or more secarate RPM switches are configured tooperate in concert.

While the foregoing tachometer features effectively inform the driver ofthe proper shift points during "drive time," further assistance isdesired. Just as golfer may review a videotape of his golf swing inorder to better refine his swing and improve his game, it is known thatsimilar training exercises can help racing drivers improve their drivingtimes.

In this regard, another significant feature found in the prior art isthe inclusion of a memory device within a tachometer. These "memory"tachometers are designed to store the engine RPM throughout a racingevent, such as a complete drag race, allowing the driver to later reviewa "replay" of the entire race.

In practice, the engine RPM is sampled at discrete time intervals ofsufficiently short duration so that the entire racing event may beaccurately recreated for later replay and review by the driver orcrewman. From this replay, the driver can identify the particular pointsat which he shifted, and determine whether he is generally shifting tooearly or too late. Advantageously, this allows the driver to makeadjustments to the timing or technique of his shifting, or engine andsuspension set-up etc., that will improve future drive times.

A related feature of these "memory" tachometers is the ability to replaythe racing event at a reduced pace, such as one-third the actualrecording speed. These tachometers also provide a time counter whichdisplays the elapsed time of the recorded event during memory replay.

While advanced features, such as those described above, allow the driverto observe dynamically the deviations between the targeted or optimumshift points and the actual shift points while the race replay isoccurring, further improvements in the art are desired. For example,further improvements are needed that will better enable drivers to moreaccurately observe the precise RPM and elapsed time at each shift point.Because of the constant movement of the deflection needle and advancingclock display, even when replaying the event at one-third speed thedriver still has difficulty in determining the precise RPM and elapsedtime at the shifting points.

It is also desired to provide a means for diagnosing possible mechanicalor electrical problems within the automobile. It is known, for example,that excessive time required to complete a gear shift may be anindication of clutch slippage. It is also known that if the vehiclerequires an excessive amount of time in any particular gear beforereaching the targeted shifting RPM, that a particular tuning adjustmentmay be desired. Accordingly, tachometers are desired that capture anddelineate upon replay certain special events that occur during therecorded event.

An additional shortcoming noted in the prior art relates to wastedmemory and/or driver distraction, since the driver typically initiatesthe event recording at some point near tie start of the race. Indeed, ifthe driver signals the tachometer to begin recording too long before thestart of the race, then an excessive amount of memory is filled withengine data that is of no use, and possibly to such an extent that toolittle memory is left to record a complete racing event. Alternatively,if the driver waits too near to the start of the race before signalingthe tachometer to begin recording, then it becomes a distraction to thedriver when his attention should be focused on the start of the race.

Another shortcoming of the prior art relates to the inability thesesystems to create a permanent record of the racing event. In the memorytachometer systems, after the driver has recorded a given racing event,he may review or replay that event, but has no means for readilygenerating a permanent record of the event. To be sure, in some priorart systems the recorded information is lost when the driver resets thedevice to record a subsequent racing event.

SUMMARY OF THE INVENTION

Accordingly, it is a primary object of the present invention to providea high performance engine tachometer capable of recording engineperformance over a given time duration and playing back that recordingat a later time, and having the added feature of detecting specialevents that occur during the recording or during memory replay.

Another object of the present invention is to provide a high performanceautomotive tachometer capable of recording an engine event, such as adrag race, and replaying that recording at a later time, and during thememory replay halting the output of the tachometer and elapsed timeclock at times of maximum engine RPMs, such as at each gear shift event.

Another object of the present invention is to provide a high performanceautomotive tachometer capable of recording an engine event, such as adrag race, and replaying that recording at a later time, and during thereplay halting the output of the tachometer at times of minimum engineRPMs, such as at the moment of full clutch engagement following eachgear shift event.

Still another object of the present invention is to provide a highperformance engine tachometer for recording an engine event, whereby therecording is automatically initiated upon the start of the race.

Another object of the present invention is to provide a high performancetachometer for recording a racing event, whereby the tachometer has anoutput signal capable of direct connection to a speaker or headset.

Another object of the present invention is to provide a high performancetachometer for recording a racing event and generating a permanentrecord of that recording.

Still another object of the present invention is to provide a highperformance tachometer for recording a racing event, whereby thetachometer has an output signal adapted for connection to a computer,whereby information recorded by the tachometer may be downloaded to thecomputer where it can be further analyzed or modified.

Another object of the present invention is to provide a high performancetachometer for recording a racing event, whereby the tachometer has anoutput signal adapted for connection to a printer for generating atangible record of the recorded event.

Still another object of the present invention is to provide a highperformance tachometer having multiple RPM switches that can beprogrammed to switch various accessories at certain preset enginespeeds.

Yet another object of the present invention is to utilize a RPM switchto provide a multi-stage shift light designed to illuminate at differentpreprogrammed engine speeds to prompt the driver to shift gears.

Additional objects, advantages and other novel features of the inventionwill be set forth in part in the description that follows and in partwill become apparent to those skilled in the art upon examination of thefollowing or may be learned with the practice of the invention. Theobjects and advantages of the invention may be realized and obtained bymeans of the instrumentalities and combinations particularly pointed outin the appended claims.

To achieve the foregoing and other objects, the present invention isgenerally directed to a high performance tachometer of the type havingan input signal indicative of the vehicular engine speed and an outputdisplay for displaying the engine speed as indicated by the inputsignal. The tachometer includes input controls for directing the controland operation of the tachometer; a memory device electrically connectedto the input signal, the memory device configured to store the value ofthe input signal at periodic and discrete time intervals, as directed bythe input controls; a special event detector configured to detect acertain predetermined event or pattern of the input signal as determinedby monitoring the output of the memory device, the special eventdetector being further configured to affect the output display upondetection of the predetermined event or pattern of the input signal; anda controller that is electrically connected among the input controls,the memory device, and the special event detector. The controller isdesigned to control and synchronize the operation among the inputcontrols, the memory device, and the special event detector.

In a preferred embodiment of the present invention, a triggering meansis included for providing an automatic start feature for the tachometermemory. Specifically, the triggering means includes a sensor ortransducer team is adapted to detect the start of the racing event, andis configured to initiate the recording sequence of the memory device.In one embodiment, the recording sequence is initiated by the driver'snormal pre-race preparations. For example, releasing the Line-Loc (frontbrakes) switch at the start of the race may initiate the recordingsequence.

In another embodiment of the present invention, multi-stage RPM switchesare provided to centrally control the operation of a plurality ofindependent devices, such as the nitrous oxide injector, the systemignition timing, and a multi-speed shift light for instructing thedriver of the optimum shift points. To be sure, controls are provided toallow at least two engine speed trigger points to be preset inconnection with the shift light feature. A separate control signal isprovided to instruct the tachometer, and thus the shift light, of theoperative preset speed. In a preferred embodiment, this separate controlsignal is provided by a selector switch configured in connection withthe vehicle gear shifter. In this manner, the particular gear that thevehicle is in determines the operative preset engine speed.

BRIEF DESCRIPTION OF THE DRAWINGS

The accompanying drawings incorporated in and forming a part of thespecification, illustrate several aspects of the present invention, andtogether with the description serves to explain the principals of theinvention. In the drawings:

FIG. 1A is perspective view of a high performance tachometerillustrating a preferred embodiment of the present invention;

FIG. 1B is a cut-away front view of the high performance tachometer ofFIG. 1A, more particularly illustrating the user input controls and thecompressed portion of the dial scale display;

FIG. 2A is block diagram illustrating several devices that an outputsignal of several preferred embodiments is configured to connect with;

FIG. 2B is an illustration of a graphical chart plotting RPM versustime, as prepared by a printer connected to an output signal of apreferred embodiment as shown in FIG. 2A;

FIGS. 3A and 3B collectively are a block diagram showing the functionalcomponents of a preferred embodiment of the present invention; and

FIGS. 4A and 4B collectively are a block diagram showing the functionalcomponents of an alternative embodiment of the present invention.

Reference will now be made in detail to various present preferredembodiments of the invention, examples of which are illustrated in theaccompanying drawings.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

Reference will now be made to FIGS. 1A and 1B which show a highperformance tachometer illustrating a preferred embodiment of thepresent invention. More particularly, a tachometer 10 having a circularface is provided and generally directed for use in high performancevehicles, especially those adapted for running high speed short durationraces, such as drag races. A single bolt mounting bracket 12 facilitatesready installation and adjustability. The circular face includes apre-printed analog readout having a double range scale 14, 16. Adeflection needle 13 is adapted to align with the point along the doublerange scale that is coincident with the vehicle engine speed.

To more particularly explain the double range scale as shown in theillustrated embodiment of FIGS. 1A and 1B, the scale spans from 0 to11,000 RMs. The first 6,000 RPMs are compressed into the lowermostportion of the scale and comprise the first "range" 14. The secondportion of the scale, or second range 16, is expanded to coversubstantially the remainder of the circular face. It should beappreciated that the second range 16 encompasses those engine speedswhich are of most concern to the racing driver, since this is the rangein which the driver will shift. Accordingly, expanding the scale in thismanner facilitates the driver's ability to shift at the appropriatecritical shift points. It should be appreciated that, although a doublerange scale is preferred, the scale could be partitioned into more thantwo ranges. For example, it may also be desirable to provide anadditional expanded scale portion around the typical idle speed.

Also included within the circular face is an digital readout 18. In thepreferred embodiment, the digital readout 18 is principally used todisplay the elapsed racing time. However and as will be discussed inmore detail below, in an alternative embodiment the digital readout 18could be utilized to provide much more information to the driver. Forexample, the precise engine speed could be digitally displayed on thereadout 18. During replay of a recorded event, the readout 18 could alsobe used to provide information such as shifting time or timing of othercritical events, which could help the driver or crewmen diagnosemechanical problems such as clutch slippage or poor engine tune. In thisway, the tachometer could be used as a diagnostic tool for the crewmenas well as a training device for the driver.

A side-mounted shift light 20 illuminates to inform the driver of theappropriate times to shift gears. While the preferred embodimentillustrates a shift light 20 as mounted to the side of the dash mountedtachometer 10, it should be appreciated that the shift light could beseparated from the tachometer 10 and mounted in any convenient andhighly visible location preferred by the driver. In this regard, a wireor some other means of electrical communication between the tachometer10 and the shift light 20 is all that is necessary.

In the preferred embodiment, the shift light is implemented by an LED 22recessed within the end of a cylindrical tube 24. Specifically, thereceiving end of the tube 24 may be adapted with a concave reflectivemounting surface (not shown) which is adapted to received the recessedLED 22. This configuration would serve to collimate the beam so that therelatively low powered LED 22 creates a highly visible beam for thedriver.

Also shown in FIG. 1A, and more particularly shown in FIG. 1B, are thevarious driver controls 30. In the illustrated embodiment, the controlsare segmented into two modules 31 and 32. The first or local module 31is attached to the face of the tachometer 10. The second or remotemodule 32 is shown as attached to the outer rim of the tachometer 10,but is detachable, whereby it can be placed in any convenient locationfor the driver's use. To facilitate the detachment, a cable 34 isprovided that electrically connects the remote module 32 to thetachometer 10. It should be appreciated, however, that other means forelectrically connecting the remote module 32 to the tachometer 10 couldalso be employed. For example, the remote module 32 could be afree-standing device in communication with the tachometer 10 throughradio frequency, infra-red, or other length electromagnetic waves. Inyet another embodiment, the two control modules 31 and 32 could beconsolidated into a single, detachable module as described in connectionwith the remote module 32.

Before discussing the features and user-controlled operations of thepreferred embodiment, a brief description of the controls is in order.On the first module 31, a two position toggle switch 36 is provided toallow the driver to select between record and replay modes. A twoposition slide switch 37 having positions labeled "TACH" and "RPM SET"allows the driver to set high and low engine RPM in connection with thetwo-stage shift light 20 previously described. Two potentiometers, onelabeled "HIGH ADJ." 38 and the other labeled "LOW ADJ." 39 are used toset a particular RPM for the high and low engine speeds that are used totrigger the shift light 20. The adjustment screw for each of thesepotentiometers is adapted for rotation by a screwdriver, and is recessedbelow the face of the control module 31. In this way, the engine speedscan be set by the driver or a crew member well before the race to berecorded, without risk of the setting being upset by inadvertent contactmade with the control panel.

The remote control module 32 has a two position toggle switch 40 labeled"REPLAY" and allows the driver to select between "PEAK" or "NORMAL"replay modes. As will be discussed further below and in connection withthe particular features provided by the preferred embodiment, when"PEAK" replay is selected the deflection needle 13 of the tachometer 10and the digital readout 18 will freeze when peak RPM readings aredetected (typically at each shift point). In contrast, when in thenormal replay mode, the entire racing event will be replayed at one-halfspeed, without pause at the various peak RPM readings. Three normallyopen push button switches are also provided on the second module 32. Theswitch 41 labeled "START" can be depressed by the driver to initiate thestart of the recording event (in the rare case that he does not want toutilize the automatic recording star feature) or memory replay,depending upon whether switch 36 (discussed below) is in the "RECORD" or"REPLAY" position. The second switch 42 labeled "STOP" is depressed tostop both the recording event and the memory replay, depending on theposition of switch 36. Finally, the third switch 43 labeled "RESET" isused to reset the tachometer memory back to the beginning of memory.

Discussion will now be more particularly directed to the features of apreferred embodiment of the present invention, and how the user controls30 described immediately above are used to effectuate these features. Aspreviously mentioned, the record/replay switch 36 is used in conjunctionwith the second or remote module 32 to control record and replayfunctions. Placing the switch 36 in the RECORD position configures thetachometer for recording a racing event, while placing the switch in theREPLAY position prepares the tachometer for replaying a previouslyrecorded event. The remainder of the controls on the local module 31 aredirected to setting the parameters for operation of the shift light 20.

The shift light 20 of the preferred embodiment is a two-stage shiftlight that illuminates to instruct the driver to shift at two separateand distinguished engine speeds. A command signal 35 (See FIG.3) is usedto instruct the tachometer 10 and ultimately the shift light 20, whetherto illuminate at the low or high engine speed setting. In oneembodiment, this input signal 35 may be generated by a selector switch29 that the driver could actuate during the race so that, for example,when the switch is in one position the shift light 20 would illuminateat the low engine speed setting, and when the switch is in the otherposition the shift light 20 would illuminate at the high engine speedsetting. In this way, if the driver desired the shift light 20 toilluminate at the high RPM setting gears 1 and 2 and a the low RPMsetting for the remainder of the gears, he would simply flip the switchafter executing the second shift.

Alternatively, and as is preferred, the low speed setting is utilizedfor first gear only, and the remaining gears utilize the high speedsetting. In this embodiment, the selector switch 29 may be mounted incooperation with the gearshift lever so that when in fist gear theswitch remains closed and the low speed setting for the shift light isactivated. Once the driver has shifted out of first gear, the switch isopen and the high speed setting for the shift light 20 is in effect forthe duration of the race. In this way, the driver need not be concernedwith releasing or flipping a switch during the racing event, but insteadcan concentrate more fully on the race. It should be appreciated that,if desired, additional switches for additional engine speed settingscould be included, allowing three or even more distinct engine speeds tobe set for triggering various external engine and vehicle controlsystems.

To set the high engine trigger speed for the shift light 20, a twoposition slide switch 37 and two potentiometers 38 and 39 are used inconjunction. Specifically, the two position slide switch 37 is used toselect between the "RPM SET" mode and normal tachometer operation("TACH"). To set the high speed setting, the slide switch is placed inthe "RPM SET" position, the gear shifter is taken out of first gear, andthe adjustment screw for the high speed potentiometer 38 is rotated toset the needle to the desired engine speed. In the preferred embodiment,and as will be described in more detail in connection with FIG. 3, asthe adjustment screw of the adjustment potentiometers 38 and 39 arerotated, the deflection needle 13 of the tachometer 10 moves to reflectthe trigger speed by pointing to appropriate value on the preprintedanalog readout. In this way, the driver can see precisely the enginespeed that is being set.

In a similar fashion, the low engine trigger speed is set by placing theslide switch 37 in the "RPM SET" position, with the gear shifter placedin first gear. A momentary switch electrically connected to thetachometer 10 and mounted in connection with the gear shifter detectswhether the shifter is in first gear. As with the high speed adjustmentdescribed above, potentiometer 39 is rotated to set the low enginetrigger speed.

In order for a driver to configure the controls 30 to record a racingevent, the two position switch 36 is placed in the RECORD position andthe RESET switch 43 is depressed. The RESET switch instructs thetachometer to go to the beginning of its internal memory and prepare torecord a first racing event. The automatic memory start feature and STOPswitch 42 then control the recording for particular racing events. Moreparticularly, the tachometer memory of a preferred embodiment, hasapproximately 40 seconds of recording capability. Therefore, sufficientmemory is provided to record several complete racing events.Accordingly, multiple racing events may be recorded by depressing theSTOP switch 42 immediately following each recorded race, but withoutagain depressing the reset button after each race is recorded. The laterraces are then stored sequentially in memory following the previouslyrecorded race.

After one or more racing events have been recorded and stored in theinternal memory, the driver may review these races by placing the toggleswitch 36 in the REPLAY position and depressing the RESET switch 43,which instructs the system to go back to the beginning of memory. Usingthe START and STOP switches 41 and 42 the driver may control the replay,stopping it at particular points of desire. Also, the memory replay willautomatically stop at the end of each recorded race. Depressing theSTART switch 41 will initiate replay of the next recorded event.

In connection with the memory replay feature, the driver can use toggleswitch 40 to select whether he wishes to view the replay in the PEAK orNORMAL modes. In the NORMAL replay mode, the race is replayed atone-half its original or recorded speed. However, in an alternateembodiment an additional user control, such as a potentiometer, can beprovided to allow the user to adjust the replay speed. In contrast tothe NORMAL replay mode, when the race is replayed in PEAK mode, both thedeflection needle 13 and the digital readout 18 halt or freeze at highand low peak positions. That is, points in which the tachometer needlechanges direction. Once the needle halts, the driver can resume thereplay of the racing event by depressing the START switch 41 once again.

If more than one racing event was recorded within the memory, replaywill automatically stop at the end of each race. Replay of the secondevent can then be initiated by pressing the START switch 41. The racingevents can be replayed a number of times simply by depressing the resetbutton 43, which returns the replay back to the start of the firstrecorded racing event, which the can be replayed by pressing the STARTswitch 41. As previously discussed, the digital readout 18 provided onthe face of the tachometer 10 functions in connection with the replayfeatures described above. In the preferred embodiment, the digitalreadout 18 displays a counter of the elapsed time within the racingevent.

Reference is now made to FIG. 2A, illustrating various features of thepresent invention in connection with an output signal. Specifically, anoutput signal 48 is generated and can be connected to a speaker or aspeaker or headset 49, a computer 50, or a printer 51. In the preferredembodiment, the output signal can be directly connected to a speaker orheadset 49. In this embodiment, the signal on the output line oscillatesat the same frequency as the instantaneous engine speed as it is outputfrom the memory device (see FIG. 3) within the tachometer 10.Advantageously, this allows the driver to listen to the replay of therecorded race, as well as reviewing it visually. To the skilled driveror crewman, certain subtleties may be detected audibly that may not bereadily apparent from the visual display. For example, hearing suddenspikes in engine speed coincident with shifting could be an indicationof clutch slippage.

The output signal 48 of the preferred embodiment may also be connectedto a specialized printer 51. This printer is termed as "specialized" inthat it has internal hardware and software specifically designed toreceive the memory output signal described above and generate a chart asillustrated in FIG. 2B to create a permanent and tangible record of theracing event. Specifically referring now to FIG. 2B, the chart generatedby the printer 51 of the preferred embodiment includes a graphicaldisplay in which the engine RPM is plotted against time. As shown fromthe graph, the high and low engine speed adjustments for the shift light20 also can be plotted on the graph so that the driver can determinefrom a quick visible glance whether, in general, he is shifting tooearly or too late. Moreover, a log of such printouts may be compiled andmaintained over a period of time allowing the driver to study hisshifting and/or racing habits to see where improvements can be made.

The information in the graph also conveys important information to thecrewmen. For example, and more specifically, the chart in FIG. 2B showsa plot of the engine speed in RPM versus time during a racing event inwhich the vehicle was shifted through four gears. The engine speed forthe duration during first gear is represented by reference numeral 52.Similarly, reference numeral 53 represents the duration of the shift andclutch engagement from first to second gear. Reference numerals 54, 56,and 53 illustrate the engine speed throughout the durations of second,third and fourth gears, while reference numerals 55 and 57 represent theengine speed during the shifts from second gear to third and from thirdgear to fourth, respectively. If, for example, a crewman were to notethat the time 56 required by the vehicle in third gear to reach theappropriate shift speed was excessive, tune-up work may need to be made.Similarly, excessive time required for clutch engagement between gearsmay indicate that clutch linkages, or clutch disc and pressure plate,are faulty or out of adjustment. Accordingly, the printed graphicaldisplay of the replay of the racing event can provide extremely useful,and perhaps critical, information to both driver and crewman.

Referring again to FIG. 2A, in an alternative embodiment the outputsignal 48 may be directly connected to a computer 50. In this regard,the necessary hardware and/or software is included within the tachometer10 to format the output signal for connection to a computer 50 througheither a standard parallel or serial link. In this way, the informationmay be downloaded to the computer 50 where it may be permanently storedon diskette. Of course, once the data is on the computer 50, it may bemore easily manipulated or displayed using either specialized or evenconventional software. Furthermore, permanent and tangible graphicaldisplays may be printed on a standard printer 65 connected to thecomputer 50. In yet another embodiment, the tachometer 10 may bedirectly connected to the standard printer 65. In this embodiment, thenecessary hardware and software is included within the tachometer 10 toformat the output signal 43 for direct connection to such a standardprinter.

Reference will now be made to FIGS. 3A, and 3B in describing theoperation of the present invention. Specifically, FIGS. 3A and 3Billustrates a functional block diagram of the present invention asimplement through discrete components, including a specialized analogmemory device. Before proceeding to the discussion in reference to FIGS.3A and 3B, however, it is important to point out that the functionalblocks shown in the figures are intended to be illustrative ofparticular features of the present invention and are in no way intendedto limit the scope of the claimed invention.

Turning now to the figure, an engine speed input signal 46 is input to amemory device 70 and also to a record/replay select logic functionalblock 72. Although not shown in the figure, it is known in the art thatthe input signal 46 is derived from the low tension side of the ignitioncoil, for standard ignition engines, and from a tachometer terminalprovided on electronic ignition cars, or other triggering devices suchas optical encoders, inductive pickups, etc. Of significance, is thatthe frequency of the input signal 46 is proportional to the frequency ofthe vehicle engine speed (the proportionality factor being determined bythe number of engine cylinders.) The memory device 70 of the preferredembodiment, is an analog memory. Specifically, the memory device is theISD1016, manufactured by Information Storage Devices, Inc. and iscommonly used in the storage and reproduction of analog speech signalsin a digital fashion. Although a detailed understanding of the devicecan be obtained from the manufacturers data sheets, such a descriptionis not presented herein as it is not deemed necessary for anunderstanding of the present invention. Moreover, the application of theISD1016 in the present invention is uniquely outside the scope of themanufacturer's intended use. Indeed, it should be appreciated that otherstorage devices, including digital memories, could be used with equalsuccess. Of course, since the input signal 46 is an analog signal, if adigital memory were selected, the appropriate filtering, sampling anddigitizing support circuitry would need to be included.

The output of the memory device 70 is directed to a signal conditioner74. In the preferred embodiment, the signal conditioner 74 isprincipally an amplifier circuit for generating the appropriate signallevel on the output signal 48 for directly driving the speaker orheadset 49 as described in connection with FIG. 2. A second output ofthe signal conditioner 74, is directed to the functional block 72labeled as record/replay select logic. As previously mentioned, theengine speed input signal 46 is also directed to this functional block,the output of which is determined by the position of the record/replaytoggle switch 36. The state of this switch 36 is directed to a centralcontroller 76 which generates a signal that instructs the functionalblock 72 to direct either the input signal 46 or the signal 77 generatedby the signal conditioner 74 to its output 78. If the switch 36 is inthe RECORD position, then the input signal 46 is directed to the output78. If the switch 36 is in the REPLAY position, then the signal 77 isdirected to the output 78.

In the preferred embodiment, the central controller 76 includes all thenecessary and appropriate circuit blocks to implement the proper controland synchronization required by the system components. Both the localand remote modules 31 and 32 of the control inputs 30 are input to thecontroller 76. A triggering means 80, master clock 82, and special eventdetector 84, which will be described in more detail below, also generateinputs to the controller 76.

In keeping with the description of a preferred embodiment, the output 78of the functional block 72 is input into a frequency to voltageconverter circuit 86. The operation of the frequency to voltageconverter 86 is dependent upon a cylinder select input 88. Specifically,an internal control setting, that is to be set upon installation of thetachometer 10, informs the frequency to voltage converter as to whetherthe vehicle is a four, six, or eight cylinder engine. The frequency ofthe signal input to the converter 86 is scaled by the four, six, oreight cylinder select switches. The resulting frequency value reflectsthe frequency value.

The scaled voltage value output from the frequency to voltage converter86 is passed through a filter circuit 87 and double range circuit 88. Ofcourse, the double range circuit 88 is included only in those tachometermodels having a double range scale as described previously. Moreparticularly, the double range circuit 88 makes the appropriatecompensations to both the low level and high level voltage values outputfrom the frequency to voltage converter 86 to effect the desireddisplacement of the tachometer deflection needle 13 in the appropriatedisplay ranges 14, 16 (See FIGS. 1A and 1B). For example, an inputvoltage corresponding to an RPM of 6000 or less is compensated in such afashion to move the deflection needle 13 only a small distance. Inputvoltage values corresponding to engine RPMs greater than 6000,compensation are compensated in a manner to effect larger needle 13deflections.

The output of the double range circuit 88, which is a continuous signal,is input to a sample and hold circuit 90 which, as the name implies,samples and outputs periodic samples of the continuous time signal inputfrom the double range circuit 88. The output from the sample and hole 90is then passed through a peak level hold circuit 92 and an air coredriver 94, which drives an air core meter 95 (described below). The peaklevel hold circuit 92 operates only to hold the output a level valuewhen a maximum, minimum, or other special event has been detected.Freezing or halting the output signal in this manner causes thedeflection needle 13 to hold steady in its current position. It can beappreciated, that the driver 94 and air core meter 95 are elements thatare known in the art and, accordingly, a detailed description of theiroperation is not necessary here.

Also illustrated in the figure are the digital readout display 18 andits associated driver circuit 89. The input for the digital display 18is generated by the controller 76, which in the preferred embodiment,causes the digital readout 18 to display a counter showing the elapsedtime of the racing event.

Further description of FIGS. 3A and 3B will be provided below, inreference to special features of the present invention. Beforedescribing these special features, however, brief reference will bedirected to FIGS. 4A and 4B which illustrate a functional block diagramof an alternate embodiment of the present invention as implemented witha microprocessor based circuit and appropriate software routines. Due tothe similarity between FIGS. 3 and 4, reference to this specificreference to FIGS. 4A and 4B is made only to point out the differencesbetween FIGS. 3 and 4.

Specifically, FIG. 4 is designed around a microcontroller ormicroprocessor based circuit 176, which includes all the appropriatesupport circuitry (e.g., ROM, RAM, decoders, etc.) required toeffectuate the operation as described herein. A clipper circuit 150 isprovided to condition the input signal 46, whereby the analog pulses ofthe input signal 46 are effectively converted into digital pulses. Thesignal conditioner 74 of FIG. 3A is removed, as the output signal 48 isdriven directly by the microcontroller or microprocessor circuit 176.

Other than these primary differences, the two embodiments operatefunctionally in a very similar manner. It should be appreciated that aperson of ordinary skill in the relevant art could design the specifichardware, whether it be using discrete components in accordance withFIGS. 3A and 3B, or microprocessor based in accordance with FIGS. 4A and4B. Accordingly, a detailed component level description is not deemednecessary.

In view of the system as set out in the foregoing description, thediscussion is now directed to more particularly illustrate severalsignificant features of the present invention.

Special Event Detection

In accordance with the concepts and teachings of the present invention,a special event detector is provided and configured to detect certainpredetermined special events, such as peaks, valleys, or any otherpredetermined event in the signal recorded and output (during replay)from the memory.

To implement this feature in a preferred embodiment, a special eventdetector circuit 84 monitors the output of the sample and hold circuit90 to detect such predetermined special events. In the preferredembodiment, the special event detector is adapted to recognize both peakand valley transitions in the output signal, which are indicative ofvehicle gear changes. This information can be used, in ways previouslydescribed, to provide valuable insight to both driver and crewmen forreviewing racing performance.

As noted in the figure, the special event detector 84, the sample andhold circuit 90, and the peak level hold circuit 92 are all disabledwhen the record/replay toggle switch 36 is in the RECORD position, andthus the tachometer 10 is in the RECORD mode. Accordingly, thedeflection needle 13 of the air core meter 95 is fluidly driven duringthe recorded racing event, and is only effected by the operation ofthese specialized circuits during the replay of the recording. Duringreplay, however, the special event detector 84 and the peak level holdcircuit 90 can be configured to halt or freeze the deflection needle 13of the air core meter 95 upon detecting a special event. The digitalreadout 18, which displays the elapsed racing time, is frozen as well.Replay is continued by depressing the START switch 41 (FIG. 1).

In an alternative embodiment, the sample and hold circuit 90 and specialevent detector 84 can be configured to monitor the input signal 46 todetect predetermined special events. These special events could then be"marked" in memory as the input signal is recorded. On replay, the"marked" memory locations would signal the peak level hold circuit 90 tohalt or freeze the output display.

Automatic Memory Start

Another significant feature provided in connection with the presentinvention is an automatic memory start feature. This feature enables thetachometer 10 to automatically sense the start of the racing event andbegin recording engine speed information therewith. It can beappreciated that this feature provides at least two distinct advantagesover systems in the prior art. First, it reduces the driver distraction,previously described, near the start of the race, by allowing the driverto focus on the racing event rather than starting the recording processon the tachometer 10. Secondly, it reduces the amount of memory requiredfor the racing event, thereby allowing more events to be recorded in thesystem memory space.

More particularly, a triggering means 80 is provided to sense the startof the racing event. In the preferred embodiment the triggering meansincludes an electrical signal driven by the Line-Loc or Transbrake(i.e., front brakes) switch. This switch is used to actuate the frontwheel brakes when the vehicle is positioned at the starting line priorto the race. Once the driver has positioned the vehicle at the startingline and actuates the Line-Loc, the tachometer 10 is automatically putinto a "ready" state. Then, when the driver releases the Line-Loc, thetachometer recording sequence automatically begins.

It can be appreciated that the triggering means 80 may comprise otherequally effective sensors or transducers for detecting the start of therace. For example, in an alternative embodiment a sensor may beconfigured to detect wheel rotation, whereby detecting wheel rotationinitiates the recording sequence. In yet another embodiment anaccelerometer may be used to detect the start of the racing event. Instill another embodiment, motion sensors, configured to detect movementof the vehicle over the ground, may be implement as the triggeringmeans. In yet a further embodiment, a light sensor may be adapted todetect the light beam that is projected across the race track and usedto start the race timing computer. These and other means consistent withthe teachings provided herein may be utilized to implement thetriggering means that initiates the recording sequence.

In another embodiment of the present invention, a temporary buffermemory is used in connection with the automatic start feature. In thisembodiment, pre-race RPM data is stored in the buffer memory. Once therace is started, as indicated by the triggering means, the contents (orat least a portion of the contents) from the buffer memory are storedinto the event recording memory. In this way, RPM data immediatelypreceding the start of the race is recorded in the memory for laterreplay. The amount of "pre-race" RPM data ultimately stored in therecording memory may be varied depending upon the design andconfiguration of the buffer memory. In effect, the buffer memory createsa sliding window during which pre-race RPM data is dynamically stored,whereby upon the start of the race, as indicated by the triggeringmeans, the RPM data stored in the memory buffer or sliding window iswritten into the recording memory.

In another alternative embodiment, controls may be provided to allow thedriver to override the automatic start feature, whereby the recordingsequence is initiated manually by pressing the START switch 41.

Multi-stage RPM switch

Another feature provided in connection with the present invention is theinclusion of a multi-stage, centralized RPM switch. As previouslydescribed, independent and dedicated RPM switches are known forcontrolling the operation of devices such as a nitrous oxide injector, ashift light, an RPM limiter, and the ignition system timing. The RPMswitch of the present invention, however, is adapted to provide acentralized control for all such devices throughout the vehicle.

Specifically, a RPM switch 21 is provided in connection with a RPMswitch adjust 100 and a RPM switch comparator 102 functional blocks. TheRPM switch adjust routine 100 provides an input to the RPM switchcomparator indicative of the engine speed at which the shift point is tobe set. Slide switch 37 is shown interconnected among the frequency tovoltage converter 36, the filter block 87, and the RPM switch comparator102. When in its upper or "TACH" position, continuity is establishedbetween the converter 86 and filter 87. However, when the slide switchis moved to its lower or "RPM SET" position, coincident with high speedor low speed engine shift point settings, a continuous circuit path iscreated between the RPM switch comparator 102 and filter 87. In this waythe shift point, as output from the RPM switch adjust block 100(ultimately derived from potentiometers 38 and 39, and the momentaryswitch mounted in connection with the gear shifter, as described inconnection with FIG. 1) is routed through the active filter 87 and othercircuit components previously described so as to drive the deflectionneedle 13 of the air core meter 95 to display the particular enginespeed set point being adjusted. It can be appreciated from the figure,that when the switch 37 is in its upper or "TACH" position, that the RPMswitch circuitry does not effect the operation of the remaining circuitelements.

When, however, the switch 37 is in its normally operative "TACH"position, the RPM switch comparator 102 compares the output of the RPMswitch adjust 100 with the output from the filter 87. If the output fromthe filter 87 is greater than or equal to the RPM switch adjust value,then the output of the shift point comparator 102 turns on so as toactivate the RPM switch 21, which, in turn, is configured to operate acontrolled device 23. In the preferred embodiment, the controlled device23 is a shift light 20 (FIG. 1), and the RPM switch adjust is adapted toprogram the shift light 20 to illuminate at two distinct engine speeds,depending upon the gear the vehicle is presently in.

It should be appreciated that the output of the RPM switch adjust block100 is controlled by controller 76 or microcontroller or microprocessorcircuit 176. Accordingly and based on the inputs, including controls 30and selector switch 29, the controller 76 or microcontroller ormicroprocessor circuit 176 can be designed so that a plurality of RPMswitches each having multiple set points that can be programmed into thetachometer. In a similar fashion, a plurality of independentlyprogrammed and operated controlled devices 23 can be controlled andoperated by the tachometer of the present invention. These controlleddevices may also include a nitrous oxide injector, an RPM limiter,system timing control, and any other device similarly operated inconnection with the vehicle engine speed.

A significant advantage of the centralized RPM switch control of thepresent invention is that the engine trigger speed for each of thecontrolled devices 23 is set or programmed through the same drivercircuitry to the air core meter 95 as the engine speed input signal 46is ultimately passed through. Accordingly, system integrity is achievedwithout the problems typically encountered by component intolerancesamong several independent and dedicated controlled devices.

Memory Pages, Partitions, and Usage

Other significant features of the present invention relates to memoryallocation and usage. Specifically, features are provided which employdynamic memory allocation so as to maximize the event storage capabilityof the present invention.

In the embodiment illustrated in connection with FIGS. 3A and 3B whichutilizes an analog memory device 70, one page of memory is provided, andis configured so as to record 40 seconds of engine speed data. In thisembodiment, multiple racing events are sequentially stored in thissingle memory page. Depressing the STOP switch after each recorded eventcauses an event marker to be placed in memory so as to delineate tosuccessively stored racing events. In this manner, successive racingevents may be sequentially stored in memory so as to achieve completeutilization of the available memory space.

In the embodiment illustrated in connection with FIGS. 4A and 4B, theavailable digital memory space is partitioned into a number of pages(four pages in a preferred embodiment). Each page is independentlyconfigured to store a number of successive racing events in the samemanner as described above for the embodiment employed in connection withFIGS. 3A and 3B. The four memory pages allow easier access to multiplerace recordings with less chance of data loss when making additionalrace recordings. Consistent with these teachings, additional memorycomponents could be added to provide even greater storage capabilities.

An additional feature provided in connection with the memory allocationis what can be referred to as a memory extension feature. In essence,this feature is a means of data compression which allows even moreracing information to be stored within the system memory space.Specifically, the input signal is sampled and converted into a two partnumber, having a mantissa and an exponent. If, at the time of the nextsignal sample, the value of the exponent portion has not changed fromthe previously stored exponent value, then only the mantissa portion isstored. With the relatively fast sampling rates of the presentinvention, frequently a single exponent value will be stored for manymantissa values, and thus requiring much less memory.

Given the memory costs and tachometer space constraints, it can beappreciated that the features described above effectively allocate andutilize the available memory space so as to maximize the system memoryusage.

Multiple Range Dial

Another significant feature c the present invention relates to themultiple range display. In the preferred embodiment the display is adouble range display, which compresses the first 6,000 RPM and expandsthe remaining 5,000 RPM (i.e., 6,000-11,000 RPM). As previouslydescribed, double range displays are known which are controlled bystepper motors. However, these systems are ill-suited for high revvingdrag racing engines due to their poor response times. Indeed, mostracing instruments utilize what is known as an air core meter 95 whichis controlled by a specialized (but well known) driver chip 94 (thedriver chip is a CS289). The air core meter 95 provides extremely fastresponse times and fluid movement of the deflection needle 13. As isknown in the art, the air core meter 95, magnetically drives thedeflection needle in an X-Y coordinate, dual torque action.

It is an advanced feature of the present invention to drive the air coremeter 95 throughout the full range of deflection, including both thecompressed and expanded scales, while also controllably providingsmooth, controlled movement of the deflection needle at the transitionpoint dividing the compressed and expanded scales. This feature isprovided in the double range circuit 88.

In one embodiment, the double range circuit 88 is implemented by analogcircuit components designed to controllably weight the signal outputfrom the filter 87, so as to effect the appropriate movement ordeflection of the deflection needle 13 of the air core meter 95.Alternatively, the air core meter 95 may be directly driven by thecontroller 76 or microcontroller or microprocessor circuit 176 in apulse width modulation fashion. In such an embodiment, the controller 76or microcontroller or microprocessor circuit 176 could include a lock-uptable to produce the appropriate pulse width modulated output toappropriately drive the air core meter 95.

Digital Display with User Prompts

Another important feature of the illustrated embodiment of FIGS. 4A and4B of the present invention relates to the utilization of the digitalreadout 18. Since the microprocessor based circuitry 176 provides greatflexibility insofar as programmable features, the digital display, inthis embodiment, is adapted to display much more than simply the elapsedtime of the racing event. To be sure, an alpha-numeric or other displaycould be used, and the microcontroller or microprocessor programmed todisplay setup or operational instructions to the driver, as well aserror messages. The display could, alternatively, be programmed todisplay a digital readout of the instantaneous engine speed. Moreover,additional displays and drivers could be included, whereby theinstantaneous engine speed as well as elapsed time or informationalmessages could be digitally displayed at the same time.

Lap Timer

Another important feature of an embodiment of the present inventionrelates to lap timing. The feature is utilized in racing vehiclesintended to repeatedly travel around a closed-loop track (i.e., a lap).In connection with this feature, a lap indicator signal informs thetachometer at the completion of each lap. Upon receiving the lapindication signal, the controller 76 or microcontroller ormicroprocessor circuit 176 inserts a "marker" into memory. During replayof the racing event, as each lap "marker" is retrieved from memory, thetachometer display is halted. Specifically, the digital readout 18displaying the elapsed time is halted, whereby the driver may observe anaccurate display of the time for the completion of that lap.

The controller 76 or microcontroller or microprocessor circuit 176 isalso adapted to insert a special code, or signal, into the output signalupon detecting the lap "marker" during replay. Specifically, when theoutput signal 48 is connected to a printer 51, the inserted code directsthe printer 51 to print a lap indication mark (a special characterindicative of the lap marker) at that point along the RPM recordingcurve. By noting the distance between successive lap indication markers,the driver can compute the lap time from an inspection of the printout.In a similar fashion, when the output signal 48 is connected to acomputer 50, the computer may be appropriately programmed to display orotherwise provide this information.

It should be appreciated that the lap indicator signal, mentioned inconnection with this lap timing feature, may be derived from any numberof sources. For example, a switch may be provided in connection with theinput controls 30, whereby the driver simply depresses the switch toindicate the completion of a lap. More sophisticated means may also beutilized. For example, a signal transmitted from the radio tower, or atransmitter operated by a crewman, or some other transmitter, mayprovide the lap indicator signal. This transmitted signal may then bereceived by a receiver provided in connection with the input controls.In this way, the lap indicator signal would be received and stored as amarker in memory in a manner completely transparent to the driver.

The foregoing description of various preferred embodiments of theinvention has been presented for purposes of illustration anddescription. It is not intended to be exhaustive or to limit theinvention to the precise forms disclosed. Obvious modifications orvariations are possible in light of the above teachings. The embodimentsdiscussed were chosen and described to provide the best illustration ofthe principles of the invention and its practical application to therebyenable one of ordinary skill in the art to utilize the invention invarious embodiments and with various modifications as are suited to theparticular use contemplated. All such modifications and variations arewithin the scope of the invention as determined by the appended claimswhen interpreted in accordance with the breadth to which they arefairly, legally, and equitably entitled.

What is claimed is:
 1. A high performance tachometer of the type havingan input signal indicative of the vehicular engine speed and an outputdisplay for displaying the engine speed as indicated by the inputsignal, comprising in combination:a memory device electronicallyconnected to said input signal; input controls for directing the controland operation of the tachometer; triggering means for automaticallyindicating the start of the drag racing event and activating said memoryin response thereto, said memory recording substantially the entirety ofsaid racing event without being reset; and a controller that iselectrically connected among the input controls, the memory device andthe triggering means, said controller controlling and synchronizing theoperation of the input controls, memory device, and triggering means. 2.The high performance tachometer of claim 1, further comprising a RPMswitch coupled to said controller for controlling the operation of aplurality of external controlled devices, wherein one of the pluralityof controlled devices is a shift light.
 3. The high performancetachometer according to claim 2, further including a manual controlswitch operated by the driver to determine an operative preset speed atwhich to illuminate the shift light.
 4. The high performance tachometerof claim 2 having an operative preset speed, wherein the operativepreset speed is determined by the gear that the transmission ispresently in.
 5. The high performance tachometer according to claims 2,further including means for driving the output engine speeds.